Bestow is a mechanic with the following reminder text:
(If you cast this card for its bestow cost, it’s an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Dictate of Erebos has the following effect:
Whenever a creature you control dies, each opponent sacrifices a creature.
Consider the following case:
My opponent controls a Dictate of Erebos
I control a single other creature, which I want to avoid sacrificing (in my case, a Doomwake Giant)
A single effect kills two of my opponent’s creatures (in my case, the Doomwake Giant’s Constellation effect triggered while he had two 1/1s)
I choose, as my first sacrifice, the Creature enchanted with the Bestowed card (in my case, the Underworld Coinsmith above)
In this situation, does the Bestowed card (e.g. the Hopeful Eidolon above) revert to being a Creature in time for me to choose it as the next sacrifice?
Or does it only revert to being a Creature after all triggered instances of Dictate of Erebos have resolved, forcing me to sacrifice the creature I want to save (e.g. the Doomwake Giant above)?